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TIMER SINCLAIR USERS CLUB 
| NEWSLETTER 


Toronto, Опіагіо | 


EXECUTIVE OFFICERS 


PRESIDENT: George Chambers (416) 751-7559 
LIBRARIAN: Martin Mauk - tapes John Burns - magazines 
ASS'T LIBRARIANS: D. Cooper ` 
T. Haller 
TREASURER: Greg Lloyd 
NEWS EDITORS: John Roach (416) 447-7784 


ACTIVITY DIRECTOR: Cameron Hayne 
LIAISON OFFICER (Out-of-town members): George Chambers 
Mike Mitchell 


LETTER FROM THE PRESIDENT 


Over the past couple of months we have had quite a few new members 
join our club, I am sure they hope to benefit from association with 
other T/S users, and often their hopes are realized. However, in the 
rush of things, I am sure some of them tend to get lost in the shuffle, 
and ultimately lost to the club. 


I would like to take this opportunity to welcome each and every 
one of you to our club, Use it, ask questions at meetings, borrow 
from our library, read the newsletter. Not the least important, 
contribute to the club activities. From my experience, you will profit 
immensely from the give and take of a more active role in the club. 
The invitation is extended; seize it. Cameron Hayne has done this, 
and has agreed to be our new Activities Director. He will be responsible 
for providing the demo's, talks, etc. at each meeting. Welcome to the 
executive, Cameron. We're pleased to have you. 


Yours in computing 
George Chambers 
(President) 


NOTES FROM THE EDITOR 


If you have an article you would like published in the newsletter, 
give it to any member of the executive during the meeting or mail 

it to SINC-LINK c/o J. Roach, 56 Pachino Blvd., Scarborough, Ontario 
MIR 4J7. 


Dan Sauve reports that nobody showed up at the 2 get-togethers he 
called to form a hardware SIG. He's still enthused - call him at 
251-5623 if you're interested. 


SYNCBITS 
Ian Robertson 


UPDATE FROM LAST ISSUE: It appears that someone is working on 

a 3TS2068/5PECTRUM interface. Apparently it is àa lot more 
complicated than simply changing bus configuration. Aerco 
(Austin Texas) is marketing a great looking TS2068 Disc System. 
Bottom line is 508.00 (US) for this complete 2 drive system 
with cabinet and 64k Ram/Bk Rom onboard. For details see their 
advert. in latest issue (HII) of T-S Horizons. 


U.K. NEWS! Two interesting items gleaned from recent issues of 
Your Computer; а) a survey of 23,000 Open University students 
with home micros indicated that Spectrum was no. 2 with 15% and 
that the ZX81 was no. 3 with 11% (of further interest was the 
face that the CBM 64 was 4th with 6% and the Apple was tied with 
the Т19 at 4%), b) a comparison between the BBC and the QL 
which makes us dedicated Sinclair types cringe a little, as the 
BBC comes out ahead. 


T82068: There are several enterprising programmers. advertising 
enhancements for the TS2050 Modem MTERM software which received 
such bad reviews because of the Documentation (ог rather,the 
lack of it). Did you know that the Spectrum version of Tasword 
II does NOT WORK with the TS2068 with Spectrum Rom. It does not 
print out! Conversely, during a conversation with 21st Century 
Electronics I was advised that a 152068 program which worked 
with the Spectrum Rom (inside a 152068) did not work on the 
Spectrum. Verrry interesting. 


TS 1000: If there still are some dedicated users out there, I 
suggest that if you want to purchase hardware items still 
advertised, that you get cracking. They will not be around 
forever. There are quite a few items available in the П.К. or 
from Integrated Data Systems (who carries most of the U.K. 
items). John Oliger is still offering his Hi-Res with colour 
kit. 


SPECTRUM ROM: 0+ all the games reviewed I must say that SABRE 

WULF by Ultimate is the best (in my opinion that ix). Two others 
deserve honourable mention, Jet Set Willy and Kokotoni Wilf. All 
three make good use 0+ graphic capabilities, The following 
languages are available for the Spectrum: Forth (several 
versions), Beta Basic (enhanced Basic), Pascal, C, Micro Prolog, 


Logo and Lisp. 


MAIL ORDER FROM U.K.: Most U.K. prices quoted in magazines 

are "Inclusive" or "Inclusive of VAT". VAT is a value added tax 
of 13% on top of the item price. Therefore deduct VAT from the 
quoted "Inclusive" price (multiplier .885) and add appropriate 
postage. On cassettes add approx. (2.00 each, to a total of 4, 
then add £0.75 for each additional. For larger items always add 
a тіп. of £5.00 to £7.50. Airmail costs are incredible, і.е. р 
£7.50 for a £mall item (if larger than standard envelope size). 


COMPUTERS AREN'T HUMAN 
Most humans use the decimal system, which consists of ten digits (0, 1, 2, 3, 4, 5, 
6, 7,,8, 9), because humans have ten fingers. The computer does not have fingers, 
so it prefers other number systems instead. Неге they are.... 


5 | BINARY 
Look at these powers of 2: 
29 =1 
21 = 2 
22 = 4 
23-8 
2" = 16 
25 » 32 
28 = 64 


Now try an experiment: pick your favorite positive integer, and try to write it 
as а sum of powers of 2, For example, suppose you pick 45. You can write it as 
32+8+4+1. Suppose you pick 74; you can write it as 64+8+2. Suppose you pick 77; 
you can write it as 64+8+4+1. Every positive integer can be written as a sum of 
powers of 2. 

Let's put those examples in a table: 
ORIGINAL WRITTEN AS A SUM DOES THE SUM CONTAIN... 


. NUMBER OF POWERS OF 2 647 32? 16? 8? 4? 2? 1? 
15 52+8+4+1 no yes no yes yes no yes 





174 644842 es no no es no es no 
es 








64+8+4+1 es no то es yes no 
To write those numbers in the inary зузфет, replace "по" by 0 and "yes" by 1: 

DECIMAL SYSTEM BINARY SYSTEM 

45 or simply 101101 

/ г 0 


















The Деетта,. Bye ber uses the digits 0, 
columns: 
thousands hundreds tens units 
For example, the decimal number 7105 means "7 thousands + 1 hundred + 0 tens + 5 units". 
The binary system uses only the digits 0 and 1, and uses these columns: 
sixty-fours thirty-twos sixteens eights fours twos wits 
‘For example, the binary number 1001101 means "1 sixty-four + 0 thirty-twos + 0 sixteens + 
1 eight + 1 four + 0 twos + 1 unit"; in other words, it means seventy-seven. 
In elementary school, you were taught how to do arithmetic in the decimal system. 
You had to memorize the addition and multiplication tables: 
DECIMAL ADDITION DECIMAL MULTIPLICATION 
3 4 5 6 7 9 0 1 2 4 5 6 7 8 


» 2, 3, 4, 5, 6, 7, 8, and 9 and uses these 


? 


3 
0 
5 





юы C UO Rt N PB 
mw CS i = C4 bor 





^ атп 
9 10 11 12 


oO) C Un i LA Jom C 


0 
0 
1 
2 
5 
4 
5 
6 
7 
8 
9 


2 09 МС CD hut! © 


10 11 12 15 


In the binary system, the only digits are 0 and 1, so the tables are briefer: 
BINARY ADDITION BINARY MULTIPLICATION 
| 0 


0 1 i 1 
0 ofo o 
11100 &босацзе доо is witten 110 1 


"10" <n binary 
If society had adopted the binary system instead of the decimal system, you would 
have been spared many hours of memorization! 

Usually, when you ask the computer to perform a computation, it converts your 
numbers from the decimal system to the binary system, performs the computation by 
using the binary addition and multiplication tables, and then converts the answer 
from the binary system to the decimal system, so you can read it. For example, 
if you ask the computer to print 45+74, it will do this: 

45 converted to binary is 101101 
*74 converted to binary is *1001010 
Eu 1110111 converted to decimal is 119 


Dame usd 

The conversion from decimal to binary and then back to decimal is slow. But the 
computation itself (in this case, addition) is quick, since the binary addition 
table is so simple. The only times the computer must convert is during input 
(decimal to binary) and output (binary to decimal). The rest of the execution is 
performed quickly, entirely in binary. 

You know fractions can be written in the decimal system, by using these columns: 
units point tenths hundredths thousandths 


For example, i2 gun be written as 1.625, which means "1 unit * 6 tenths * 2 hundredths * 


8 
5 thousandths". 

To write fractions in the binary system, use these columns instead: 
units point halves fourths  eighths 


For example, 12 is written in binary as 1.101, which means "1 unit * 1 half + 0 fourths + 
1 eighth". 
You know i is written in the decimal system às 0.3333333..., which unfortunately 


s : i : : 1, : 
never terminates. In the binary system, the situation is no better: zis written 


as 0.010101.... Since the computer stores only a finite number of digits, it cannot 
1 EST : 
store = accurately—it stores only an approximation. 


A more distressing example is т. In the decimal system, it's .2, but in the binary 


system it's .0011001100110011.... So the computer can't handle = accurately, even 


though a human can. 
Suppose you enter this on your ZX-81l computer: 


PRINT "MY FAVORITE NUMBER IS ";4.001-4 


The computer will try to convert 4.001 to binary. Unfortunately, it can't be con- 
verted exactly; the computer's binary approximation of it is slightly too small. 
The computer's final answer to 4.001-4 is therefore slightly less then the correct 
answer. Instead of printing MY FAVORITE NUMBER IS .001, the computer will print 
MY FAVOURATE NUMBER IS .0010000002 . Other computers come up with numbers like 
.000999987 , 

To test your 7Х-81'5 accuracy, try 4.0001-4, and 4.00001-4, and 4.000001-4 etc. 
you might be surprised at its answers. 














ALL 2 nd Zrectrum prearams TERRE REN Е _ 
эге i ÁJrecorded an tape if PROGRAMS STRUCTURE 
one n2 e бєгїп. These 
FRETA am ве Figure zhows some Of the 
^2 iproaram) Easit tion of a Prearam. ALL 
EN TELES] of the сагат would be on tape 
oy т SBE iii fated ih Fiaufre 2. 
IHE CODE (butes) This i typical G-section 
5 ргоага ith basic, screen and 
Basic Programe мша! | iust tade. LE Line ЭЙ whith i5 the 
have a bazic section but save | » FLL programs „Жш. 
С machine code rroarzinz have 2 ar a LWA MS WE а SANE line, 
; 8 sections, These could include this o! the basic is saved bu 
| the bazit Section, maybe a Em diee "T 7 
| Ае and at Least one code ZOUE "example" LINE 20 
== : 
ECU This means that whem the saved 
| REDATE is loaded, it ш 
\ automaticatlu ag to Line AO. 
| herefore ine ZU if cattle & 
! PERDER autoestart Line CF S bon ts 
| мег sertian nn tape it Line 2а instructs ta L "s" 
геа а bs a header. This is SCREEMS so that the. screen wilt 
the short part that loads when load while the tape is still 
the border shows blue & red running, Then line 39 will Гоар 
stripes. After a header has mc" which are the machine Code 
Loaded, the.title of the bytes. This is the tast section 
section mitt Usually appear on fo be Loaded zo line 40 PRINTS 
screen, Besides the title, the а message to stop the tape 
header also Loads im the length Plauer, 
and starting address of the 
eection, The rest of the program is then 
ExXECULEd and somewhere in the 
basic there will be an 
instruction to access the 
machine code that was 
previousLu Loaded. (This if done 
With the USR command), As the 
header af gath section uas 
loaded. the screen would have 
disrigsued Figure 3, however, 
a SCREENS would cover up part 
FIGUGE of ait. 


LORD "s" SCREENS 
LORE "me" CODE 


FIGURE 2 


г 


PLS : PRINT "Stop Tape" 


etic..etct...... 


Maw 

4 uu enm ia =ч 

yam dn onm] dno 
мита 


m zu meu 
In em Ке Жы" 


c niu 
Oc?» 


(Basic Program) 





STOP 













FIGURE 3 


SAVE “Еехамтр|е” LINE 20: 
"s" SCREENS: SALVE "mc'"CODE 


STOP Program: example 





bytes: Е 


bytes: 









me 





зи. 











г шоп t i ace 
or the basic wie 
L sin а TAVE line рне ki xeu 
and not know where the LUR CODE 
su UR Mer n iD pot erase this from youi 
compzter Stree 1 
То LL these Problems, we аж 
us isl utility program Immiiistziu atop the tape 
tt iz ия 2 Load a header thi: point. — ы йы 
ari it and it gives us кат om 
ali the required information. ———— 
One such utility is called Е ны 
"Header". TO USE it we first р ое 
load it in and just Follow the = . 
directions on the screen. The SAVE "=" 
header Gf each section is шы Е 
loaded in with "Header" and we HOTE 3 =f | 
Сап read the needed info on the АРЕ 
sereen andor iet the printer fis: E 
ОИ Therefor 
saved it 
SAVE "2" CODE 16364,6912 


6. LORD in the last section 
(machine code) from the 
LET’S TRY IT Original tape With: 


LORD "" CODE 

















1, We Mill make = back-up oF 
ihe proaram in Figure 1, The Ts Gave Fi: rode and indicat 
First ziep is te Ghtain the the sddrezz it is to be pui 
following information amd the Length or it. 
+Наме of esch section, ZAVE "mc" CODE 40000,1208 
&Huto-ztart iine GF basic, 
Stapi address of each code In the Sample the 48000 is 
E£&ciion, and fus Je TE ар of En 
| code ап 2ай is е numbe; 
xLenath of each COde section Se Rule Cono 1s e ERE 
If this cannot be recadillu must be included Whenever 
obtained bu looking for the faving code, 
fgve Line in the basic, then 
YOU must use a special $. If the program has more 
utilitu such as "Header". sections just repeat the 
E procedure for the extras,.ai 
2. How Load in only the basic if there are fewer, omit 
section of the Proaram in those. How you mag Wish to 
one of tuo ways., Ome Way is verify everything using: 
te LORD "" and BREAK when it [n 
has Loaded the first section WERIFY "" 
In zome Programs чои may | 
na Е арїє io BEZAR, For . io check the basic and: 
these uou myst toad them "m 
using: НЕРСЕ "". This will VERIFY "" CODE 
Cauze & break automatically . 
at the end of the first fhe code. vou can 
section. Tru to stop the У the SCREENS за 
tape player right at the end over at when 
Gf this Bection ЕС that it 
is positioned at the start 
Gf the second section. 
3. This bassiC Can now be saved 
onto your back-up tape bu: 
НЫЕ "example" LINE 20 




















PROGESHH ING TRICKS 
us БЕ using the Sane 
ThE titi Of the basic program E Griginet unless 
MILL aiu dz Frint on screen = the proaram 
When 115 header is logged, but nasmez. 
the titie of i OF OL Lona 
ЕС: ИЕ if = times not =. 2 in doubt whether 
shown, This i done bu makina ЕС: ПМ is Е agren 
the ink Sand paper the rise or Пе code, Load it 
colour before that section i£ With: LOADS "" CODE 
loaded. Obtain the hidden title . 
bu the wee of "Header", =. £times uou will not need 
use the Header Utility. 
When the basic section if 2 Programs have all the 
loaded and you with to BREAK etsay info in 8 Save. 
the loading process at the end = in the basic section, 
Of the section, uou may ae a 
crash of it mau keep an 4. When faving a screen, it 
loading. This trick is done by ИНЕТ БЕ Present on the Tu 
a FORE in ThE suto-start Line Screen nr it Will Mot save, 
Or Бч the ON ERR command, : 
Overcome this problem bu load- 5. If the basic has а save Line 
ind the basic With the MERGE uot can GOTO this Line te 
Command. Save all sectione but Note 
| #4 applies. When Saving more 
Sometimes there is a blank area than one section by using 
Of tape between sections. This the fave Ling, be ready ta 
WoUld be needed for the basic Press a key when Prompted. 
46 do something before the Line | 
that loads the next section, $. Mote that throvahout this 
For €. amt LE, the “Upload Оса" Srticle, I have used the 
Program dots a short display term "back-up" в: opposed tn 
ГРИН СЕ ЕЛ the basic and 5 "copy", Even though we are 
thé Machine code. Be sure to desting With Making as copy 
ameert this came tenath СЕ nr cupLicate nf an original 
tlàn! im your baàtk-UuP. YOU can Program, ihe term "back-up" 
determine this lenath bu timina haz 3 more legat fring to jt! 
st or With the tape counter, 
Integrated Data Systems 
30 Brookmount Road, Toronto, Ontario IL ЗМІ 
416-443-5518 (Answer-phone) 

Please note that we have moved and that the above is our new 
address and phone number. We still have а full catalogue of 
ZXB8':/TS:1000 items although this is decreasing all of the time. 

We have publication rights to software from Ezra Group II, 
Hargrave, Woods plus other authors under our own name. We alsn 
believe that we are the Only company in North America selling 
Centronics and RS232C Interfaces that are port mapped not memory 
mapped, The Dual Centronics is $89 and the Dual RS232C is $149. 


Both come with 


along with 
evailable. 


2958’ s can all 


EPROM Poards 


software on 
and some of 


$24.96.  TS1829'5, 


be provided 


on consignment, 


We scrept 
wriless there 
printsez 


VISA, Mt 


ere books where it is +5, or 


nr modems. 


tape but we can alse provide on EPROM 
the most useful utilities 
We also carry books such as Mastering MC at 
and RDM Disassembly ARB at 


$15.99 
TS RAMS 2949? and 


Piss some used equipment that we sel] 


2 


or cheques and charge 1,50 PRH/order 


+5 if computers, 


A HEADER РЕОБРАМ FOR THE 


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Practically the 
is to be found i 
book Explorers 
ZX81'. Hou I ney 
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USE OF THE 7 IN FUNCTION 
ju G Е Chambers 

It is sometimes desirable to be 
able to use tuo keys at ihe _ 
same time, Many games could be 
improved with this Capabilities 
On the Т52958 this 1% BOGS sins 
through the use of ine 'IH 
function.The fol lowing Table Я, 
and Ftch-a-Sketch demonstration 
program till illustrate this 
possibility. 


IN 


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an ETC KA-SKETTH ТУРЕ 
of drauing routine ta 
illustrate the USE oF 
the IN runct 
the Т52 058 
Б БЕН _ 
T REM Bu G 
а RE р = 
а REM Use key a 
rar cur А 
lise КЄ 
Ноа: ce H 
18 LET x=125: LET =a E 
2A IF IN 54510 -30 AND yilve TH 
EH LET yeuystl == 
зв IF IN 55022 =за AND yuri THEN 
zu-: 






ETGS42 =ЗА AND imma TH 
7348 2228 ANG xii THEN 
SALES 4:31 THEN GO 305 
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uh to ЕГЗЕЕ а 
tar = 3 bulk 
eras af away should 
it b other tapes? 
Arte = number of 
EXPE oncluded that 
ther = major cancern 
РОГ rasure of 
prog img, is а List 
or t {t= Which did 
not ect on a short 
prz- aram. 
x Hoving s head-demagni fier 
around the tape, 





+ 
Pep 
"ап 
a e 


e 





+ 


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= 


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u 
antact with colour 
hile it was turned 


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fuk a 


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т 
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1 
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+ 
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[nad vt 


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tape under a telephone 
it rang 5 times. 


SCREEN COPIES on the 
inter with tape in 
With printer. 


+ Held tase about 1 (ONE) inch 
From bulk tape eraser while 
turning eraser orf & оп and 
mawvina tape around!!! 

Я kargar zresnker 3 t [ e.a! 

B nr.) would pro erase the 

(rogram, Likewis ing the 

tape within 1" û bulk 

eraser ji: “Goodby aram": 
eyen if the eras switched 
on & OFF nce Н: ‚ this if 
nat cons = a tal. 






Sa why b baut. 
erasing = program? 
The real sguzeée ror 
Lost ora careless 
finger б Button. 


41 T1 





Du 














IS 
SPECTRUM TS 2068 
BOTTOM TOP BOTTOM TOP 
GND GND 
SPKR/ TAPE EAR 
+15 v ATR 
+ бу 0, 
N.C. N.C. 
PWR GND Do 
PWR GND 
{ CLK t 
i Ao L] 
| ^, , 
| А, 3 
i А» 4 
i А. В INT 
АВ AMI 
А.В НАСТ 
A MREQB 
А, юкаВ 
А, RDB 
As WRB 
As BUSAK 
А, WAIT 
А, BUSRQ 
А, RESET 
А. MI 
N.C RFSHB 
RGB Red EXROM 
RGB Grn ROSCS 
RGB Blu BE 





BOTTOM 


SIDE B 


ZX - 8l 





ROMCS 


TOP 








7 МЕЛ Hardware Meus 
by Peter N°Mullin for ТЕ. С. 27/85 #1 in a Series for the ADVENTUROUS, COMMITTED 7X8! Owner. 


took advantage of the great price on GLADSTONE 64K RAM packs 

isable the 8K-16K block, so they can use 

some of the many peripherals which are mapped to that area. To this end, 

I have drawn an improved schematic of the 664К for reference, and written 

an article, with documented schematics, outlining the necessary procedures. 
А simple address decoder and MREG NOT gating does the trick. 

with options depending on required switching flexibility. In fact, although 

not mentioned in the article, this method could be used to selectively 

disable ANY block of memory between O & 64k! | 

The details are too involved to relate here, sa I have placed copies 

of the project manual in the CLUB LIBRARY: it is available there 

for those who require it. 


Many who 
have expressed the need to d 


or info on using the cheap but nifty 
EXCELTRONIX 5" Greenscreen monitor. (I just found the file:) | | 

The problem is with the supplied sync separator, NOT with the monitor itself. 
My solution involves using the partial sync-separation provided by the | 
Random Access VIDEO INVERTER circuit, which was published as a construction 


project in Computers k Electronics, May 'B83 issue. А5 with the G564K project, 
l will place full details in the LIBRARY as soon as I can prepare the material. 


Apologies to those waiting f 


erm 


Т am composing this text on my 64K 7Х81. outfitted with a surplus Appl 
lone keyboard, using Word Sinc II. Text is output on an EPSON MX-BO printer, 
іа the EPROM SERVICES Centronics interface and software driver, 
hich 1 recently purchased fron Integrated Data Systems. 
ft 4u encouraging to report that MEMDCALC, and ZX PRO-FILE (Centronics 
JE чето) both print out just fine with the EPROM SERVICES I/F and software. 
utput of the printer CTRL and «ESC- codes, so valuable ín wordprocessing, 

з a sticky subject, though. I BREAK from WSII menu, t LFRINT At to do it here. 

I am currently awaiting replies from both P. Hargrave and EPROM SERVICES 
regarding WSII.4 compatibility. Things seem promising, so I^11 keep you posted. 






My final topic for this issue is the most exciting. 
I recently received documentation on the long-awaited ZXB1 Video Upgrade 
project, created by John Dliger, 11601 Whidbey Dr., Cumberland, IN 46229. 


The following features should make you sit up and take notice: 
1) SLOW mode is 5.5X normal speed. i.e. same as 2068. Some M/C games 


run TOO FAST, and arcade-speed games in BASIC become possible! 
FAST mode, as usual at 6X normal SLOW speed, is BLINK-FREE! 
2) You get COLOUR VIDEO with UPPER and lower case on screen, as an 
alternative to inverse characters. Colour control is equiv. to 2068. 
з) Machine code can now run anywhere in 464K, with free use of the IX register, 
and schemes using vectored hardware Interrupts may be supported. 
4) System is completely transparent to existing software. 
5) Display File CRASHES are NO HORE! 


The project consists of two circuit boards. one for the TMS9718 Video 
Display Processor (which supports SFRITE graphics) and 16K Video RAM. 

The other circuit board holds an enhanced(i.e. display routines rewritten) 
versian of the ZXB1 ROM, which it overrides. А Motherboard оғ" cable is required. 
Mr. Oliger sells both boards, and all parts except the VDP and it s crystal 

for $48.95 U.S. (Quick! Where's my checkbook?) Write to him for details. | 


Discoveries like these make the AERCO Disk System for the ZX81 
seem more attractive all the time to a hardware addict like me. 
But that's for another discussion. Ho рух Com pat Хр"